The God of War series, over its Greek and Norse eras, isn't exactly known for its humour and lightheartedness. While the Greek era was all about Kratos being angry while killing Gods, the latter has – as Odin succinctly put – also been about Kratos killing Gods, but while being sad about it. However, Kratos' travels through the Nine Realms have surely been a bit more cheery, in no small part thanks to his companions. While Mimir, the Huldra brothers, and even Atreus tended to lift the mood at times, Ragnarok introduced a character which some devs thought was a bit too much.
Look back at every entry in the series, and try to remember the sheer magnitude of the foes that Kratos faced. Not once did he ever freeze in fear or confusion. Yet, when faced with a slightly large, one-eyed, talking squirrel, the Ghost of Sparta stopped dead in his tracks and just couldn't seem to comprehend this well-mannered, jolly, and cute furball. Ratatoskr, as we eventually learned, is the caretaker of Yggdrasil, and one of the most lighthearted characters in the entire series. Watching grumpy old Kratos trying to interact with him brings a moment of levity during the events of Ragnarok.
However, director Eric Williams had to work hard to make sure he wasn't cut from the game. “I wanted this character in the game,” said Williams in an interview with GameInformer. “I wanted him to do these things and everyone was like, ‘We have to cut this. We have too many characters.’ And I was like, ‘No! He’s staying in the game.’”
However, it wasn't easy for him to convince the rest of the team that Ratatoskr should stay. “That scene where he shows up? That was the one everybody was like, ‘Okay, are we going too far?’” Williams says. “Even the music director was like, ‘I don't even know what to do with the music here. This is so far away from God of War. We don't even have music written that will help this along!’ They had to go back and piece some stuff together for it because it was so foreign to what God of War is.”